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/filesystems/unixfs/common/linux/kernel/lib/parser.c

http://macfuse.googlecode.com/
C | 228 lines | 121 code | 21 blank | 86 comment | 26 complexity | 47dedbf2d1d620217b3d47ac2016e934 MD5 | raw file
  1/*
  2 * lib/parser.c - simple parser for mount, etc. options.
  3 *
  4 * This source code is licensed under the GNU General Public License,
  5 * Version 2.  See the file COPYING for more details.
  6 */
  7
  8#include <linux/ctype.h>
  9#include <linux/module.h>
 10#include <linux/parser.h>
 11#include <linux/slab.h>
 12#include <linux/string.h>
 13
 14/**
 15 * match_one: - Determines if a string matches a simple pattern
 16 * @s: the string to examine for presense of the pattern
 17 * @p: the string containing the pattern
 18 * @args: array of %MAX_OPT_ARGS &substring_t elements. Used to return match
 19 * locations.
 20 *
 21 * Description: Determines if the pattern @p is present in string @s. Can only
 22 * match extremely simple token=arg style patterns. If the pattern is found,
 23 * the location(s) of the arguments will be returned in the @args array.
 24 */
 25static int match_one(char *s, const char *p, substring_t args[])
 26{
 27	char *meta;
 28	int argc = 0;
 29
 30	if (!p)
 31		return 1;
 32
 33	while(1) {
 34		int len = -1;
 35		meta = strchr(p, '%');
 36		if (!meta)
 37			return strcmp(p, s) == 0;
 38
 39		if (strncmp(p, s, meta-p))
 40			return 0;
 41
 42		s += meta - p;
 43		p = meta + 1;
 44
 45		if (isdigit(*p))
 46			len = simple_strtoul(p, (char **) &p, 10);
 47		else if (*p == '%') {
 48			if (*s++ != '%')
 49				return 0;
 50			p++;
 51			continue;
 52		}
 53
 54		if (argc >= MAX_OPT_ARGS)
 55			return 0;
 56
 57		args[argc].from = s;
 58		switch (*p++) {
 59		case 's':
 60			if (strlen(s) == 0)
 61				return 0;
 62			else if (len == -1 || len > strlen(s))
 63				len = strlen(s);
 64			args[argc].to = s + len;
 65			break;
 66		case 'd':
 67			simple_strtol(s, &args[argc].to, 0);
 68			goto num;
 69		case 'u':
 70			simple_strtoul(s, &args[argc].to, 0);
 71			goto num;
 72		case 'o':
 73			simple_strtoul(s, &args[argc].to, 8);
 74			goto num;
 75		case 'x':
 76			simple_strtoul(s, &args[argc].to, 16);
 77		num:
 78			if (args[argc].to == args[argc].from)
 79				return 0;
 80			break;
 81		default:
 82			return 0;
 83		}
 84		s = args[argc].to;
 85		argc++;
 86	}
 87}
 88
 89/**
 90 * match_token: - Find a token (and optional args) in a string
 91 * @s: the string to examine for token/argument pairs
 92 * @table: match_table_t describing the set of allowed option tokens and the
 93 * arguments that may be associated with them. Must be terminated with a
 94 * &struct match_token whose pattern is set to the NULL pointer.
 95 * @args: array of %MAX_OPT_ARGS &substring_t elements. Used to return match
 96 * locations.
 97 *
 98 * Description: Detects which if any of a set of token strings has been passed
 99 * to it. Tokens can include up to MAX_OPT_ARGS instances of basic c-style
100 * format identifiers which will be taken into account when matching the
101 * tokens, and whose locations will be returned in the @args array.
102 */
103int match_token(char *s, match_table_t table, substring_t args[])
104{
105	const struct match_token *p;
106
107	for (p = table; !match_one(s, p->pattern, args) ; p++)
108		;
109
110	return p->token;
111}
112
113/**
114 * match_number: scan a number in the given base from a substring_t
115 * @s: substring to be scanned
116 * @result: resulting integer on success
117 * @base: base to use when converting string
118 *
119 * Description: Given a &substring_t and a base, attempts to parse the substring
120 * as a number in that base. On success, sets @result to the integer represented
121 * by the string and returns 0. Returns either -ENOMEM or -EINVAL on failure.
122 */
123static int match_number(substring_t *s, int *result, int base)
124{
125	char *endp;
126	char *buf;
127	int ret;
128
129	buf = kmalloc(s->to - s->from + 1, GFP_KERNEL);
130	if (!buf)
131		return -ENOMEM;
132	memcpy(buf, s->from, s->to - s->from);
133	buf[s->to - s->from] = '\0';
134	*result = simple_strtol(buf, &endp, base);
135	ret = 0;
136	if (endp == buf)
137		ret = -EINVAL;
138	kfree(buf);
139	return ret;
140}
141
142/**
143 * match_int: - scan a decimal representation of an integer from a substring_t
144 * @s: substring_t to be scanned
145 * @result: resulting integer on success
146 *
147 * Description: Attempts to parse the &substring_t @s as a decimal integer. On
148 * success, sets @result to the integer represented by the string and returns 0.
149 * Returns either -ENOMEM or -EINVAL on failure.
150 */
151int match_int(substring_t *s, int *result)
152{
153	return match_number(s, result, 0);
154}
155
156/**
157 * match_octal: - scan an octal representation of an integer from a substring_t
158 * @s: substring_t to be scanned
159 * @result: resulting integer on success
160 *
161 * Description: Attempts to parse the &substring_t @s as an octal integer. On
162 * success, sets @result to the integer represented by the string and returns
163 * 0. Returns either -ENOMEM or -EINVAL on failure.
164 */
165int match_octal(substring_t *s, int *result)
166{
167	return match_number(s, result, 8);
168}
169
170/**
171 * match_hex: - scan a hex representation of an integer from a substring_t
172 * @s: substring_t to be scanned
173 * @result: resulting integer on success
174 *
175 * Description: Attempts to parse the &substring_t @s as a hexadecimal integer.
176 * On success, sets @result to the integer represented by the string and
177 * returns 0. Returns either -ENOMEM or -EINVAL on failure.
178 */
179int match_hex(substring_t *s, int *result)
180{
181	return match_number(s, result, 16);
182}
183
184/**
185 * match_strlcpy: - Copy the characters from a substring_t to a sized buffer
186 * @dest: where to copy to
187 * @src: &substring_t to copy
188 * @size: size of destination buffer
189 *
190 * Description: Copy the characters in &substring_t @src to the
191 * c-style string @dest.  Copy no more than @size - 1 characters, plus
192 * the terminating NUL.  Return length of @src.
193 */
194size_t match_strlcpy(char *dest, const substring_t *src, size_t size)
195{
196	size_t ret = src->to - src->from;
197
198	if (size) {
199		size_t len = ret >= size ? size - 1 : ret;
200		memcpy(dest, src->from, len);
201		dest[len] = '\0';
202	}
203	return ret;
204}
205
206/**
207 * match_strdup: - allocate a new string with the contents of a substring_t
208 * @s: &substring_t to copy
209 *
210 * Description: Allocates and returns a string filled with the contents of
211 * the &substring_t @s. The caller is responsible for freeing the returned
212 * string with kfree().
213 */
214char *match_strdup(const substring_t *s)
215{
216	size_t sz = s->to - s->from + 1;
217	char *p = kmalloc(sz, GFP_KERNEL);
218	if (p)
219		match_strlcpy(p, s, sz);
220	return p;
221}
222
223EXPORT_SYMBOL(match_token);
224EXPORT_SYMBOL(match_int);
225EXPORT_SYMBOL(match_octal);
226EXPORT_SYMBOL(match_hex);
227EXPORT_SYMBOL(match_strlcpy);
228EXPORT_SYMBOL(match_strdup);